The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Although no longer the most popular choice in consumer motor vehicles (passenger cars, sport utility vehicles and light trucks), the manual transmission and clutch were originally and for many years the sole powertrain speed and torque matching components available. Nonetheless, for certain uses and for certain consumers, the manual transmission and manual clutch remain the speed and torque matching components of choice. The absolute and positive control of the vehicle powertrain, generally better fuel economy and freedom of operation offered by such components to the driver has not been duplicated in even the most sophisticated automatic transmissions.
The freedom of operation is not without drawbacks, however. For example, selection and operation in a gear ratio, i.e., fourth or fifth, which is too high for the current vehicle speed results in lugging by the engine and sluggish vehicle acceleration. Engagement and disengagement of the clutch by the vehicle operator which is excessively slow or preventing full engagement of the clutch by resting a foot on the clutch pedal causes excessive wear of the clutch surface and can significantly shorten clutch life. A downshift which skips a gear, i.e., a fourth to second gear downshift or a fourth to first gear downshift, can cause dramatic increases in clutch disk speed which can damage the clutch disk and, again, shorten its life. Newer manual transmissions with multiple cone synchronizers can achieve synchronization with much larger speed differentials than single cone synchronizers, thus generating even higher, vehicle driven clutch disk speeds during skipped gear downshifts. Clutch failures which are the result of such overspeed constitute approximately 20 percent of the total of clutch failures. While such drawbacks are generally associated with drivers who are either unskilled or unfamiliar with the vehicle, it is apparent that intervention by vehicle systems could reduce or eliminate some or all of these problems. The present invention is so directed.